Base for electric lamps or similar devices



A. GREINER 2,392,661

BASE FOR ELECTRIC LAMPS OR SIMILAR DEVICES Jan. 8, 1946.

Filed Aug. 10, 1944 [/v v5 70R. A L FRED Q/vE/NER MA M Patented Jan. 8, 1946 BASE FOB ELECTRIC LAMPS OR SIMILAR DEVICES Alfred Greiner, Cleveland Heights, Ohio, assignor to General Electric Company, a corporation of New York Application August 10, 1944, Serial No. 548,891

9 Claims. (Cl. 176-32) This invention relates to envelope and base construction for electrical devices, including lamps and discharge devices which at present generally have vitreous envelopes, and it involves novelty in construction as well as in manufacture. The invention is especially advantageous for devices whose envelopes have tubular necks or end portions, and is hereinafter explained in connection with double-ended tubular discharge lamps of low-pressure positive column type, and particularly fluorescent lamps of this character. The lamps may be either of the general coldstarting type exemplified in U. S. Patent No. 2,114,842 to Inman, or of the present commercial hot-starting typ referred to in U. S. Patent No. 2,212,427 to Peters. The invention aims to provide a simple, strong end and base construction and to facilitate both the manufacture and the final basing of the devices. It is very suitable and gldgeantagcous for circularly or helically bent lamp Various other features and advantages of the invention will appear from the description of species and forms of embodiment, and from the drawing.

In the drawing. Fig. 1 is a side view of a lamp tube equipped with end discs suitable for the purposes of this invention, an intermediate portion of the tube being broken out and omitted and an end disc and an adjacent portion of the tube wall being partly broken away; F18. 2 is a tilted view of such a lamp tube after it has been coiled; and Fig. 3 is an end view of a tube such as shown in Fig. 1 or in Fig. 2.

Fig. 4 is a tilted side and sectional view of a tube based according to this invention; Fig. 5 is an inside end view of the base shown in Fig. 4;

. and Fig. 6 shows a section of the tube end, taken as indicated by the line and arrows 8-6 in Fig. 3.

Fig. 7 is a tilted side and sectional view similar to Fig. 4 illustrating a modified construction; Fig. 8 is an end view of the tube end illustrated in Fig. 7; and Fig. 9 shows a section of the tube end, taken as indicated by the line and arrows 9-9 in Fig. 8.

Fig. 10 is a tilted inside end view of a modified base.

As shown in Fig. 1, the lamp comprises a tubuiar envelope l permeable to light or other desired radiation, and usually of vitreous material, such as the soft glass of which fluorescent tubes are commonly made. Mounted across the ends of the tube I are thermionic cathodes 2, 2 of suitable coiled or coiled-coil tungsten fllment type, preferably activated by being coated or charged with alkaline earth metal oxide(s) such as a mixture including barium and strontium oxides. with each cathode 2 may be associated the usual unemissive auxiliary anodes 3, 3, preferably formed by the transversely extending ends of current lead-wires 4, 4 between which the filament 2 is connected. The current leads 4, 4 may be sealed through the envelope ends 5, 5 in various ways; as here shown, they are sealed into a pressed seal 6 at the end of a stem tube I. An inner exhaust tube 8 is shown opening through the seal 8 at one end of the lamp, and extending out through the corresponding stem 1 to a point outside the envelope and 5, where it is sealed oil. at 9. The envelope i may contain a low-pressure atmosphere of starting gas, such as argon at a pressure of 2 to 4 mm. of mercury, and also a vaporizable and ionizable working substance such as mercury. A supply of mercury, which may exceed the amount that will vaporize during operation of the lamp, is indicated by a drop I l inside the envelope l, and an internal coating of fluorescent material or phosphor I! on the envelope walls is also indicated.

As thus far briefly described, the device corresponds essentially to fluorescent tubes already lmown, this summary description of known features being intended as a background for the description of other features with which the present invention is more especially concerned.

As here shown, the envelope 1 has at its ends projecting shoulders, preferably formed by outward-enlarged apertured central protuberances or bosses l3, IS on the tube ends 5, 5, which in the present instanc consist of sheet metal discs (as of chrome iron, commercially known as A1- legany against which the glass tube ends abut, and to which they are sealed by fusion. These end discs 5 resemble those shown in U. S. Patents Nos. 2,154,550 to White and Johnson and 2,114,842 to Inman, but are flat with the bosses I I turned outward instead of inward. Besides affording a hold for the attachment of bases as hereinafter described, theshoulders l3, II also aiford a grip by which the ends of the straight tube I can be held to bend the tube (when softened by suitable heat) into a circle or into one or more coil convolutions, as illustrated in Fig. 2. The stem tubes 1 may be fused and sealed directly to the inner sides of the discs 5 around the openings into the bosses it, while the envelope tubes I are sealed to the inner sides of the discs inside their marginal flanges. Thus the construction diflers somewhat from that shown in U. 8. Patent No. 2,154,550 to White and Johnson, which it broadly resembles.

The base l4 shown in Figs. 4 and comprises a cylindrical shell having an end web I! that carries hollow contact terminals It, It in the form of tubular biposts, and also having an inturned flange i1 around its end opening or mouth opposite the web, adapted to flt around the neck of a tube end boss II and to interlock behind the shoulder and in the constriction ailorded by the enlarged head of the boss. To facilitate passing the shell flange II over or around the boss IS, the shell is shown with a number of longitudinal slots i4 extending from near the end web through the mouth flange ll, so that the base I4 can be easily and quickly snapped on the boss. As shown in Fig. 4, the current leads 4, 4 extend from inside the tube I out through the stem I and the apertured boss is into the contact terminals I, II, to which they are suitably secured and electrically connected. To prevent the base l4 from turning on the boss it after it has been snapped on the boss, the base may be antiturningly engaged with the boss or the envelope end 5, as by means of key lugs I9, is formed by shearing out tongues of the sheet metal at the top of the boss I I and bending them back or retroverting them to lie outside the boss and engage in correspondingnotches II, 24 in the flange II, as more clearly shown in Pig. 6. This not only prevents the lead wire; 4, 4 from being brought into contact, but allows of definitely orienting the contact terminals II, I! as desired, relative to the tube I and its cathodes I, 2 and to one another. As shown in Fig. 4, the base I4 is a cap-like shell of molded flber or other insulation having suitable elasticity.

In practice, the leadwires 4, 4 may be threaded through the contact pins or posts I, it before snapping the base l4 on the boss l3, and afterward drawn taut, soldered, brazed, or squeezed fast in the pins, and cut of! flush with the ends of the latter.

Figs. 7, 8, and 9 illustrate a modification in which the tube-end shoulder for interlocking en- 45 gagement in the bas I4 is resilient. In the present instance, the resilience is provided by means of a springy wire ring 2i snapped and thus locked in place around the circumferentially constricted base portion of the apertured boss n.

with its ends at opposite sides of a single key lug l9. While this lug I! might be formed by retroversion of a tongue as in Fig. 6, it is shown in Fig. 9 as formed by merely shearing the tongue out of the sheet metal of the boss I3 near the 55 flat part of the disc 5 and bending or deflecting it outward at its root and also inward nearly to a right angle at mid-length. A shown, the shell of the base i4 is of sheet metal and the insulative end web I! that carries the biposts I, I6 60 ly to allow of snapping the shell around it. As

here shown at l8, some resilient expansion of the shell mouth is also provided for, by slotting the 70 shell (in one place) from its mouth upward nearly to the web I.

Fig. 10 illustrates a modification of the base shell to provide !or keying it against rotation when it is snapped on the boss l4.

I'brthis purpose, the shell wall is slit and pressed inward adjacent its mouth, thus providing oppoud square shoulders 23, 23 to engage at opposite sides of the key lug is when the base is applied to the tube end shown in Figs. 8 and 9 and snapped around its boss II and resilient ring II. In this case, the resilience of the ring II is mainly relied on, since the base shell is not slotted to provide for resilient expansion thereof as in Fig. 7.

In Figs. 6. 7, 8, and 9. and 10, various parts and features are marked with the same reference characters as their homologues in other figures. as a means of dispensing with repetitive description.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The combination of a vitreous tube with a metal end disc abutting and sealed to the tube end and presenting at its outer side an integral, projecting, apertured boss circumferentially constricted adjacent the disc proper.

2. The combination of a vitreous tube, a metal end disc abutting and sealed to the tube end and presenting at its outer side a projecting boss circumferentially constricted adjacent the disc proper, and a vitreous stem inside said tube having its end sealed to said metal end disc.

3. The combination of a coiled vitreous tube with its ends alongside its intermediate portion and presenting projecting shouldered bosses, and snap-on bases engaged around and interlocked behind the shoulders of said bosses.

4. The combination with a vitreous tube having an end wall with a projecting shouldered boss at its outer side circumi'erentially constricted adjacent said end wall, of a base comprising a shell resiliently snapp d around said boss and interlocked behind its shoulder in said constriction.

5. The combination with a vitreou tube and a metal disc sealed to the tube end and presenting a projected shouldered bossat its outer side circumferentially constricted adjacent said disc proper, of a base comprising a shell engaged around and interlocked with said shoulder, and having contact terminals exposed at the exterior of said base.

6. The combination with a vitreous tube presenting a projecting resilient shouldered boss at its end, of a base comprising a shell snapped around said resilient shoulder and interlocked behind the same.

7. A device of the character described comprising an envelope with an end wall having at its outer side projecting apertured protuberance circumferentially constricted adjacent said end wall. a base comprising a shell engaged around and interlocked with said protuberance, and having hollow contact terminals exposed at the exterior of said base, and current leads extending from inside the envelope out through said apertured protuberance into said contact terminals, and electrically connected to the latter.

8. A device of the character described comprising an envelope with a metal end disc sealed thereto and having a shouldered and apertured external boss, a spring enga ed around said boss and interlocked behind its shoulder, a base comprising a shell engaged around said spring and having an inturned edge interlocked behind said spring, and an end wall with contact terminals exposed at its outer side, electric translation means in said envelope carried by said metal end disc. and current leads from said electric transiation means extending out through said boss into said contact terminals, and electrically connected to them.

9. A method of fabricating and basing a coiled vitreous tube with its ends close alongside its intermediate portion; which method comprises iusing and sealing the tube ends to abuttin metal discs presenting external projecting shoulders and carrying at their inner sides electrical translation means, with current leads extending 10 out through. the discs; soitening the tube. and coiling it as aforesaid by holds on said discs; threading on said current leads hollow contact terminals of bases having shells, and snapping and interlocking the base shells around and behind said disc shoulders; and electrically connecting said contact terminals to said current leads.

ALFRED GREINER. 

